Have SVGTextContentElement inherit SVGGraphicsElement

Have SVGTextContentElement inherit SVGGraphicsElement

Have SVGTextContentElement inherit SVGGraphicsElement instead of
SVGStyledElement in order to match the latest SVG2 specification:
https://svgwg.org/svg2-draft/text.html#InterfaceSVGTextContentElement

This patch also removes the SVGTransformable and SVGLocatable IDL
interfaces as they are no longer needed (were merged into
SVGGraphicsElement in the latest specification).

Conversion to absolute (user agent) coordinates in the svg/text
tests is fixed to use SVGGraphicsElement::getScreenCTM() instead
of SVGGraphicsElement::getTransformToElement(). The previous code
was working until now due to a bug in getTransformToElement(),
which was not taking into consideration the CTM of the
SVGTextElement (as it was not recognized as a "locatable" element).
Now that SVGTextElement inherits from SVGGraphicsElement, it is
properly recognized as a "locatable" element by
getTransformToElement().

This is one step towards getting rid of multiple inheritance in
SVG.

BUG=256600
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=153432

[Stephen Chennney, 2013-07-02 16:24:43]

lgtm

[commit-bot: I haz the power, 2013-07-02 16:24:55]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ch.dumez@sisa.samsung.com/18503004/6001

[commit-bot: I haz the power, 2013-07-02 17:50:52]

Change committed as 153432